Keller, W. (2001). The geography and channels of diffusion at the world's technology frontier. National Bureau of Economic Research.
芝加哥风格引文Keller, Wolfgang. The Geography and Channels of Diffusion at the World's Technology Frontier. Cambridge: National Bureau of Economic Research, 2001.
MLA引文Keller, Wolfgang. The Geography and Channels of Diffusion at the World's Technology Frontier. National Bureau of Economic Research, 2001.
警告：这些引文格式不一定是100％准确.